Michael Regan/Getty Images
Before we get started, here are a few fantastic young defenders who have been impressing as of late, and who could, if given time to develop and further experience on the pitch, could very well crack this list at this time next year.
Phil Jones and Chris Smalling: The two young defenders at the heart of the new generation of "Fergie's Fledglings," Manchester United's Phil Jones and Chris Smalling have been impressing left and right, and both can count Fabio Capello among their fans, as each have already had appearances for England so far this season.
Martin Kelly: The versatile 21-year-old fullback has shown incredible promise, making a strong start to the season following some struggles with injury. All four of his appearances for Liverpool so far this season have ended in victories for the Reds, with his first resulting in a clean sheet. Fellow recent addition José Enrique looks strong at left-back, and should Liverpool return to the top four and get more exposure in Europe, he could very well be a candidate for this list as well.
Kieran Gibbs: A graduate of the Arsenal youth academy, left-back Kieran Gibbs has begun to show more consistency and confidence on the pitch as of late. If he continues to improve, he could very well be one of the top defenders in the Premiership in the future.
Mamadou Sakho: The 21-year-old Paris Saint-Germain centre-back has already established himself as a leader and a hot prospect for the January transfer window. A highly diligent, highly physical player, Sakho has emerged as a capable leader at PSG despite his age—so much so, that upon his arrival at the club, he became the youngest captain in Ligue 1 history, a title he still holds today.
Micah Richards: The Manchester City centre-back hasn't gotten a whole lot of time in the spotlight in favor of the bigger, badder Vincent Kompany, but his versatility and strength made impressed when he started at City at the age of 14 and became the youngest defender ever to get an England cap in 2006 and now, as part of a re-energized City side. If he can break back into the first team and continue to deliver, he's certainly a contender to be on a future incarnation of this list.